Science

Brain aging could explain why time feels like it moves faster as we get older

Brain aging could explain why ...
A new hypothesis suggests as we grow old our brains process less images at a slower pace, and it is this that speeds up our sense of time passing
A new hypothesis suggests as we grow old our brains process less images at a slower pace, and it is this that speeds up our sense of time passing
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A new hypothesis suggests as we grow old our brains process less images at a slower pace, and it is this that speeds up our sense of time passing
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A new hypothesis suggests as we grow old our brains process less images at a slower pace, and it is this that speeds up our sense of time passing

The subjective sense that time moves faster as we get older is a universal one, and over the years scientists have proffered a number of different explanations as to why this happens. A professor of mechanical engineering at Duke University is suggesting a new and strange hypothesis to explain the phenomena, and it has to do with our aging brains.

One of the common psychological explanations behind our sense of time moving faster with age is that the more familiar the perceptual information around us is, the less attention we pay to it. Children, for example, are constantly perceiving new events and environments, using significantly more brain power to process day-to-day information. As we get older, the novelty of our reality slowly tapers off, leaving one with the sense that time is passing more rapidly.

Adrian Bejan, a mechanical engineer at Duke University, has taken this idea and offered a more solid, physical explanation to underpin the phenomena. While we certainly may have processed more information when we were young, giving us the sense of time moving slower, Bejan he claims this to be the result of younger brains being able to identify and integrate mental images at a much more rapid pace.

"People are often amazed at how much they remember from days that seemed to last forever in their youth," says Bejan. "It's not that their experiences were much deeper or more meaningful, it's just that they were being processed in rapid fire."

Bejan's idea is that physical features of our brain that degrade with age underpin our sense of time speeding up. For example, our saccadic frequency is known to decline as we age. This is our ability to perceive single mental images, and studies in infants have revealed younger eyes move around a scene much faster than adults. Bejan suggests this shows younger minds acquiring and integrating more information faster than older minds, and it is this higher load of perceptual data that results in a subjective sense of time moving slower while young and faster when old.

"The human mind senses time changing when the perceived images change," says Bejan. "The present is different from the past because the mental viewing has changed, not because somebody's clock rings. Days seemed to last longer in your youth because the young mind receives more images during one day than the same mind in old age."

Bejan's proposal is undeniably compelling, presenting a neurological mechanism that could reasonably explain the subjective perception of time speeding up with age. However, this purely physical mechanism doesn't entirely explain the seemingly consistent and exponential increase in the speed of time passing from year to year as we get older.

The logarithmic hypothesis fills this gap, suggesting time perception is relative to the proportion of time we have lived. So proportionally, a year to a 10 year old feels much longer than a year to a 50 year old. As Christian Yates, a mathematical biologist from the University of Bath, explains, the perceived experience of time from the age of 10 to 20 is the same proportionally as from 40 to 80.

"To a 10-year-old, a year is only 10% of their life, (making for a slightly more tolerable wait), and to a 20-year-old it is only 5%," Yates explains. "On the logarithmic scale, for a 20-year-old to experience the same proportional increase in age that a two-year-old experiences between birthdays, they would have to wait until they turned 30. Given this view point it's not surprising that time appears to accelerate as we grow older."

All of this certainly leaves us with the unsurprising conclusion that time is complicated, and our perception of it, even more so. Bejan's new idea may be somewhat accurate but it surely is only one piece in the bigger puzzle that is our subjective experience of time.

The article was published in the journal European Review.

Source: Duke University

12 comments
Nobody
There is one other perception of time as we get older. We realize that we are very rapidly running out of it. Each day becomes more urgent to get the things done that we wanted to do. You never hear the young discussing their bucket lists.
Brian M
Same thing is seen when going on holidays - The first few days seem to last forever, new experiences, new images . After the first week it then just flies by. Which fits in with both the 'new image' theory and 'logarithmic hypothesis' of time perception. Doing nothing while waiting for something to happen also seems to alter our the perception of time, which is seen in the common sayings - 'a watched kettle never boils' and 'like watching paint dry' . Which goes against the 'new image' theory of stretching perceived time. As does those boring school lessons!
JonathanPDX
I always figured it was because as we age we have more and more experiences for the brain to sort and catalog and compare with every other experience in order to put it them in the right place within the brain. As our brains are more engaged in these activities, it has less time to mark the passing of time; the time intervals it perceives are spaced farther apart making it seem that time is moving at a much faster pace, even though it it actually passing at the same rate.
BrianK56
I once asked my young sons if time seemed to be going by fast for them. They both answered yes.
GordonHoffman
Good theories, but does it explain why the new water heater I bought a couple of years ago is actually 10 years old?
guzmanchinky
The key, I have found at 48, is to banish repetitiveness. Novelty is the only way to slow down time. I spend my life now traveling the world in my van and motorcycle, always trying to find new things to see and do. If there isn't a day where I can look back and say "yep, that was the day I climbed x" or "that was the day I first visited y" then I consider it a slightly wasted day. There are so many more people now realizing that a "normal" life in an office with two kids is so comfortable as to be terminally boring...
Douglas Bennett Rogers
The logarithmic scale is built into everything. In the young universe you have big stars forming and blowing up very fast. In the old universe you have only red dwarfs that last trillions of years.
Thinker
I think our minds, as we get older are preparing us for eternity, whatever meaning you want to apply to the term “eternity”.
William Lee
My Theory is that there is just More and More Crap that we're Exposed to and Quite Aware of, but that we've already decided that We Don't Need to Bother With Very Much of It.
owlbeyou
A friend once jokingly said something worth mentioning here: "When you're ten years old, life goes 10mph, and when you're fifty, 50mph". The young are busy interpreting and absorbing a lot of information and images, this is certainly true, but that shouldn't stop older folks from doing the same, and even more of it. Some people grow old, and some grow up. Routine is probably the culprit here, as some of the posters allude to. If you had the luxury (and tenacity) of taking away all the clocks, computers, cell phones, radios and TV's in your home and paid attention only to your circadian rhythms, would that make a difference? Maybe not.